A number of garage door operators have been sold over the years. Most garage door operators include a head unit containing a motor connected to a transmission. The transmission, which may be a chain drive or a screw drive, is then coupled to the garage door for opening and closing a garage door.
Such garage door operators also typically include a wall control unit, which is connected via one or more wires to the head unit to send signals to the head thereby causing the head unit to open and close the garage door. In addition, these operators often include a receiver unit at the head unit to receive transmissions from a hand-held code transmitter or from a keypad transmitter, which may be affixed to the outside of the garage or other structure.
The garage door operator may be actuated in a variety of ways. For example, a user may punch a button or enter other types of information at a transmitter to actuate the garage door operator. Some previous garage door systems also included a clock or other timing device, which was used to actuate the door at certain times of the day. The clocks in these previous systems received energy to operate from a battery or were hard-wired to a conventional electrical power supply.
The disadvantage of using these previous arrangements is that manual re-synchronization is required if power to the clock were lost or the clock for some other reason lost synchronization. Manual re-synchronization of these systems is also time consuming for the user to accomplish and inconvenient, since power loss often occurs during periods of inclement weather or at night making it difficult to accomplish the task.
Because of the need to eliminate the need to manually re-synchronize the system, a battery backup for the clock is employed in some previous systems. However, the use of this additional component necessarily increases the cost of the garage door system. In addition, the battery itself needs to be replaced from time to time further inconveniencing the user.
Previous system are also incapable of adjusting time when time changes occur. For example, when the time changes from standard time to daylight savings time or vice versa, previous systems must be manually re-synchronized. Furthermore, since it is unknown where (and in which particular time zone) the system is to be positioned, synchronization of the system is needed at least once (during system initialization) in order to set the time of the system to the correct local time.